Air motor

ABSTRACT

The following specification describes an air motor formed of three coaxial cylinders or housings assembled by a simple threading operation with one end housing having a spring biased valve assembly detachably inserted therein for directing air to opposite piston sides. A shuttle in one housing controlling the valve assembly is guided by a sleeve bearing to minimize wear, and a conduit transmitting air from the valve assembly to the opposite end housing is simply connected by a single pair of fittings.

Umted States Patent 1 3,699,846 Stomper Oct. 24, -1972 [54] AIR MOTORFOREIGN PATENTS OR APPLICATIONS Inventor: Joseph p n Norridge. 45s,2217/1949 Canada ..91/346 [73] Assignee: Stewart-Warner Corporation,

Chicago 11 Primary Examiner-Martin P. Schwadron Assistant Examiner-IrwinC. Cohen [22] 1970 Attorney-Augustus G. Douvas, William J. Newman [21]Appl. No.: 102,720 and Norton Lesser 52] US. Cl ..1 ..91/346, 91/342[57] ABSIMCT [51] Int. Cl. ..F0ll 31/02, FlSb 13/04 The followingspecification describes an air; motor Field of Search ..91/342, 344, 37, 3 337 formed of three coaxial cylinders or housings assembled by asimple threading operation with one end [56] References Clted housinghaving a spring biased valve assembly UNITED STATES PATENTS detachablyinserted therein for directing air to op- I posite piston sides. Ashuttle in one housing con- 2,215,852 Klell'l 342 X troning the valveassembly is a leeve bear- ..L iing to wear and a conduit transmittingair 2,637,304 5/1953 Dinkelkamp ..91/346 X from the valve assembly tothe opposite end h i is 2,707,456 5/1955 Schwexsthal ..91/ 342 X Simplyconnected by a single pair f fitti g 2,740,384 4/1956 Dinkelkamp et al...91/337 2,745,387 5/1956 Dinkelkamp ..91/342 X 1 Claim, 8 DrawingFigures ALI (1 &

PATENT ED110124 m2 lmm INVENTOR Joseph M. SYomper By (MW AflornevPATENTED um 24 I972 SHEET 2 [1F 3 INVENTOR Joseph M. Sfomper 4 PM ATTornev FIG.3

PATENTEDnm 24 m2 SHEET 3 [1F 3 m v Attornev INVEN TOR Joseph M. StomperAIR Moron BACKGROUND OF THE INVENTION Air motors such as typified inU.S. Pat. No.

2,637,304 incorporate a valve operator or shuttle for tripping a slidevalve from one limit position to another as the piston approaches eachend of its stroke. The slide valve in respective limit positionsconnects the air supply to respective opposite piston sides forreciprocating the piston. The valve operator is snapped to its limitposition by a pair of snap acting spring toggle assemblies which createa large eccentric load on the valve operator, which in turn slides onthe piston rod so that the inner or smaller surface of the valveoperator bears the load. The valve operator or shuttle, therefore, tendsto wear relatively quickly.

In addition, the slide valve is located in an internal chamber at oneend of the piston cylinder where it is inaccessible without majordisassembly of the motor and conduit that passes air between the valveand the piston side remote from the valve. A relatively complicated andexpensive arrangement, therefore, results which requires relativelycomplicated and time consuming assembly procedures for replacement orrepair.

SUMMARY OF THE INVENTION The present invention proposes an improvementin the described air motor by providing a valve assembly which isinserted through a wall passageway from exterior of the air motor andclamped in position by several bolts so that the valve assembly may bereplaced or repaired without disassembling the motor. An outwardlyextending rib on the valve assembly has a passageway axially alignedwith an exterior conduit transmitting air to the side of the pistonremote from the valve assembly to reduce the number of fittings orcouplings. The valve operator or shuttle is supportedalong its exteriorsurface by a bearing sleeve to provide greater load distribution andminimize wear.

Further improvements in the air motor are provided by constructing themotor in three coaxially aligned shells or housings which are engaged bymeans of threads to couple the air motor into a unitary structure withthe minimum of parts and labor.

Accordingly, it is a primary object of the present invention to providean improved and more economical air motor.

It is another object of the present invention to provide a more durableair motor capable of facile servicmg.

Other objects and features of the present invention will become apparenton examination of the following specification and claims together withthe drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view ofthe air motor incorporating the principles of the present invention;

FIG. 2 is a sectional view taken along the line 22 in FIG. 1;

FIG. 3 is a top elevational view of the air motor seen in FIG. 1;

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3;

FIG. 5 is a partial sectional view illustrating the connection of thevalve assembly to the air motor;

FIG. 6 is an isometric view of the shuttle valve assembly;

FIG. 7 is a rear elevational view of the cylindrical member of the valveassembly; and

FIG. 8 is a sectional view taken along the line 8-8 in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 an air motor isindicated generally by the reference character 10. The motor 10 includesa piston or air cylinder or chamber 12 seen in FIGS. 2 and 4 and definedby central annular shell 14 having threads at opposite ends. One end ofthe chamber 12 is closed by a second shell or housing 16 threadinglyengaging threads at one end of shell 12 and a third shell or housing 18closes the opposite end of chamber 12. A ring nut 20 having an internalshoulder engaging an external shoulder on housing 18 is threaded on theopposite end of shell 14 to clamp the housing 18 to shell 14. Ring seals22 are provided between the shell 14 and each housing 16 and 18 toprevent leakage. v

A conventional piston 24 is adapted to be reciprocated in chamber 12between the housings 16 and 18. A trip rod 26 and a piston rod 28project in respective directions along the central axis of the piston 24into a respective central passageway '30 inhousing 16 as seen in FIGS. 2and 4, and a respective central passageway 32 in housing 18. One end ofpiston rod 28 is secured to piston 24 by means of a nut 33 and is sealedin passageway 32 by a packing 34 to prevent air leakage from chamber 12.The other end of the rod 28 is accessible from the exterior of housing18 and is threaded or otherwise formed to enable the piston rod of apump, for example, to be connected thereto for operation by the airmotor. A central cavity 35 is provided in rod 28 for receiving a reduceddiameter portion 35a at one end of rod 26 and a cap 35b secured to theend of the reduced portion 35a.

Rod 26 in central passageway 30 is also sealed against leakage by asealing assembly 36 and the passageway 30 is closed at its upper end bya plate 38 secured thereto by bolts 29. A cap 40 is secured to a reduceddiameter portion at the upper end of rod 26 to provide a pair of spacedshoulders 41 and 42 for engaging respective shoulders 44 and 46 formedon the internal surface of a shuttle 48.

The shuttle 48 is a generally annular sleeve sup ported for slidingaxial movement along its external surface by axially spaced bearingsleeves 50 and 51 secured in body 16. A pair of spaced shoulders 52 and54 are formed in the outer surface of shuttle 48 for engaging a slidevalve 56 of a valve assembly 58 in response to reciprocation of thepiston 24 to opposite ends of chamber 12 for the purpose of applying airunder pressure to opposite piston sides, as will be explained. Air underpressure is supplied through a port 60 intermediate the ends of housing16 and around shuttle 48 to the valve assembly 58.

A pair of spring loaded snap action toggle assemblies 62 such asdescribed in the aforementioned patent are provided in housing 16 forthe purpose of ensuring that the shuttle 48 moves the slide valve 56 toopposite limit positions as the piston 24 moves toward the end of itsstroke. A toggle 64 for each assembly 62, having one end seated in arespective ball socket in shuttle 48, pressurizes a pair of coaxialsprings 65 in the respective toggle assembly in response to movement ofthe piston and after the toggle is moved slightly past a position whenthey are coaxially aligned with the springs, the

springs release their stored energy to drive the shuttle to a limitposition through the toggle and thereby ensure the valve 56 is moved toa limit position.

The valve assembly 58 is seated in a radial bore 66 of housing 16opposite port 60 and controls the communication of inlet pressurized andexhaust air from port 60 to and from respective sides of piston 24. Asseen in FIG. 6, the valve assembly 58 comprises a cylindrical member 68having an annular recess 70 formed along the outer periphery adjacentone end thereof and a boss 72-formed thereon adjacent the same end.

Boss 72 has a pair of elongate straight parallel sides 74 and arcuateends or sides 75 for nested engagement in a correspondingly shapedaperture 76 formed in a ring 78 that engages against the adjacent end ofmember 68. An O-ring 80 is seated in the recess 70 and is sandwichedbetween ring 78 and member 68 to seal the bore or passageway 66 againstthe leakage of air.

Three pair of passageways or apertures 82, 84 and 86 are formed in boss72 with a center pair 84 adapted to be either placed in communicationwith pair 82 or pair 86 by a recess 88 formed in one surface of slidevalve 56. The valve 56 has parallel straight sides 90 and arcuate endsor sides 92 for alignment with respective sides of opening 76 of ring78. The distance between arcuate sides 92 is less than the distancebetween the corresponding sides of aperture 76 so that the valve 56 maybe slid between the arcuate ends of aperture 76 to place openings 84 incommunication with opening 86 through recess 88 while leaving openings82 in communication with central passageway 30 when the valve is at itsupper position as seen in FIGS. 2 and 4. Alternatively, openings 84 .areplaced in communication with openings 82 and openings 86 are incommunication with central passageway 30 when the valve 56 is in itslower position.

The valve 56 is held in abutment with. boss 72 by a spring 94 whichstraddles the valve 56. A pair of depending legs 96 formed on spring 94are secured to member 68 by means of screws such as 98 extending throughapertures in ring 78 into threaded openings 99 in member 68 so thatmember 68, ring 78, O-ring 80, valve 56 and spring 94 form a subassembly100 of assembly 58.

Subassembly 100 is clamped to a cap 102 by means of a pair of bolts 104which extend through apertures in the cap 102, through respectiveapertures 106 in a sealing gasket 108 and into threaded openings 109 inmember 68 to complete the assembly 58. Cap 102 with the gasket 108 areseated in an enlarged portion of bore 66 adjacent the outer wall ofhousing 16 with the gasket 108 seated against a radial wall 110 of bore66 to seal the bore. Bolts 112 extending through openings 114 in gasket108 secure the cap 102 and the assembly 58 t0 the housing 16 so that theentire assembly 58 may be disassembled from housing 16 by simplyunscrewing bolts 1 12 accessible from the exterior of housing 16.

Cap 102 is provided with a central exhaust passageway or aperture 116which communicates through an aperture 118 in gasket 108 and apassageway 120 formed in member 68 with the apertures 84 in boss 72.Opening 116 also extends through a boss 122 formed intermediate the endsof a rib 124 extending radially of bore 66 on the external surface ofcap 102 and internal threads permit receipt of an ap' propriate fittingto carry away or muffle exhaust air. A second boss 126 formed at thelower end of the rib 124 has a passageway or opening 128 thereinextending radially of bore 66 to receive a conduit 130. Opening 128communicates with a passageway 132 extending axially of cap 102 andparallel to opening 116 and in turn communicates with a ring passagewayor recess 134. Recess 134 is formed by a pair of spaced ringshapedbosses 135 and 136 on the inner surface of cap 102 engaging gasket 108with boss 135 encircling boss 136. Recess 134 in turn communicates witha passageway 138 in gasket 108, which in turn communicates with apassageway 140 formed in member 68 and in communication with apertures86. I

Conduit 130 is sealed with O-ring 141 at one end in opening 128 andextends axially of piston 24 and rod 28 assembled toward housing 18. Anut 142 and conventional ferrule are provided at the opposite end ofconduit 130 for threading engagement with an L- shaped fitting 144projecting from a threaded radial passageway 146 in housing 18.Passageway 146 in turn communicates with a passageway 148 in housing 18extending axially of piston 24 and opening into the piston chamber 12for the purpose of communicating either inlet air to the lower side ofthe piston 24 or exhaust air therefrom.

Openings 82 in boss 72 communicate with-an axial passageway l50 and inturn communicating with a radial passageway 152 in member 68 forcommunication with a passageway 154 in housing 16. Passageway 154extends axially of piston 24 and communicates with chamber 12 for thepurpose of either passing inletair to the upper Side of piston 24 orexhaust air from the upper piston side.

Assuming the piston 24 is in the position shown in FIG. 2 and inlet airunder greater than atmospheric pressure is applied from a source, notshown, through an appropriate fitting threaded in port 60, the operationof the air motor 10 will now be described. The inlet air is transmittedthrough an opening 156 in housing 16 aligned with port 60, the centralpassageway 30, apertures 82 in boss 72, passageway 152 in member 68 andpassageway 154 to the upper side of piston 24 to thereby force thepiston downwardly in chamber 12. The air on the lower side of the pistonis simultaneously exhausted to atmosphere through passageway 148,fitting 144, conduit 130, passageways 128 and 132, passageway or recess134 in the inner surface of cap 102, opening 138 in gasket 108,passageway 140 in member 68, openings 86 in boss 72, recess 88 in valve56, openings 84 in boss 72 and passageways 120, 118 and 116 toatmosphere.

As the piston 24 moves downwardly a predetermined distance, the nut 33engages shoulder 35c of cap 35b to move the trip rod 26. The shoulder 41of cap 40 on rod 26 then engages shoulder 44 on shuttle 48 to move theshuttle downwardly with the annular shuttle being provided with bearingsupport along its outer surface by the annular bearing sleeves 50 and51. As the shuttle 48 moves down, the toggles 64 apply pressure to thesprings 65 of toggle assemblies 62 and after the toggles 64 pass theiraxially aligned position with the springs 65, the spring pressure isreleased causing the toggles 64 to move the shuttle 48 independently ofrod 26. The movement of shuttle 48 in response to the release of springpressure engages shoulder 52 with valve 56 to rapidly shift the positionof valve 56 to the opposite end of aperture 76 in ring 78 for thepurpose of preventing any motor stalling as may occur in the event thevalve slowly exposed both sets of apertures 82 and 86 to inlet air.

With valve 56in its opposite limit position, apertures 86 are nowexposed to inlet air under pressure and apertures 82 blocked therefrom.The inlet air is passed through aperture 86 and passageways 140, 138,134, 132 and 128 to conduit 130 through fitting 144 and passageway 148to force the piston 24 upwardly. Simultaneously air is exhausted toatmosphere from the upper side of piston 24 through passageways 154, 152and openings 82, the valve recess 88, openings 84, and passageways 120and 116.

As the piston 24 moves upwardly a predetermined distance, the nut 32engages the shoulder between reduced diameter portion 35a and the normaldiameter of rod 26 to carry rod 26 upwardly. The shoulder 42 on the rod26 then engages shoulder 46 on the shuttle 48 to move the shuttleupwardly. As the shuttle 48 moves upwardly, the toggles 64 applypressure against the springs 65 in toggle assemblies 62 to store energytherein and, as the toggles move past the axis of the springs, thesprings release their energy to drive the shuttle 48 rapidly to itsupper limit position. As the shuttle 48 moves into its upper limitposition, shoulder 54 thereon throws the valve 56 back into the positionshown in FIGS. 2 and 4, whereafter the piston 24 is caused to reverseits movement. Thus, the piston 24 is reciprocated to drive the rod 28 inrespective directions and thereby operate a device such as a pumpconnected thereto. It will be appreciated, of course, that the motor canalso be driven in response to the application of other pressurizedfluids or the use of a vacuum.

lf replacement of one of the components of assembly 58 becomesnecessary, the coupling 142 is simply disengaged from fitting 144 andthe conduit 130 disengaged from passageway 128. The bolts 112 aredisengaged from housing 16 and the cap 102 is grasped at rib 124 tofacilely remove the assembly 58 from the housing 16. The malfunctioningcomponent of assembly 58 may then be replaced or repaired as required bydisengagement of bolts 98 and/or 104 and subsequent reassembly ofassembly 58 into housing 16.

Access to the interior of shell 14 is easily provided by simplyunthreading housing 16 from shell 14 after disassembly of conduit 128and/or ring nut 20, which arrangement likewise permits facilereassembly.

The foregoing constitutes a description of an improved air motor whoseinventive concepts are believed set forth in the accompanying claims.

What is claimed is:

1. An air motor comprising a shell defining a piston chamber, onehousing threadingly engaged with said shell for closing one end of saidshell to define one end of said chamber and having a pair ofcircumferentially spaced radial passageways therein with one of saidradial passageways adapted to receive air under pressure, a piston insaid chamber movable in opposite directions, a second housing, means forthreadingly engaging said second housing with said shell for closing theother end of said shell to define a respective other end of saidchamber, a piston rod for said piston extending axially into said onehousing, a valve, a member received in the other radial passageway ofsaid one housing and having three passageways therein with one memberpassageway located intermediate the other member passageways, a ringseated against one face of said member with said ring having an openingtherein for receiving said valve in abutment with one face ofsaidmember, said ring opening having one pair of spaced sides defining aguideway for said valve and another pair of spaced sides each defining arespective limit position for said valve, a plate spring having a flatface overlappingly engaged with said valve, screw means securing saidspring and ring to said member for holding said ring in abutment withsaid member and said valve movably engaged with said member one face toselect one of said other member passageways for communication with saidone member passageway and the other of said other member passageways forcommunication with said one housing one radial passageway in accordancewith the limit position to which said valve is moved, an O-ring seatedbetween said member and ring and engaging the periphery of said onehousing other radial passageway for sealing said other radial passagewayagainst the passage of air, a cap overlapping said one housing otherradial passageway having a pair of cap passageways therein with one ofsaid cap passageways aligned with said member one passageway and theother cap passageway aligned with a respective one of said othermemberpassageways, said cap one passageway adapted to communicate saidmember one passageway with atmosphere, a single sealing meansoverlapping said one housing other radial passageway interposed betweensaid member and said cap and having means communicating said one cappassageway with said one member passageway and said other cap passagewaywith said respective one of said other member passageways, meanssecuring said cap to said member, a plurality of bolts threaded intosaid housing and extending through said cap and sealing means forsealingly securing said cap and member to said housing with said one cappassageway in communication with said one member passageway and saidother cap passageway in communication with said respective one of saidother member passageways, an axially extending passageway in said onehousing communicating said one end of said piston chamber with the otherof said member other passageways, a passageway in said second housing incommunication with said respective other chamber end, a conduit havingone end inserted into said other cap passageway, a pair of seriallyconnected fittings for connecting the other end of said conduit to saidsecond housing passageway to communicate said chamber other end withsaid other cap passageway and the respective one of said member otherpassageways, a shuttle relatively movably mounted on said piston rod andmovable with said piston rod and engaging said valve, a snap actingspring toggle assembly for driving said shuttle to a 8 V passagewayswhile the other of said other member passageways is in communicationwith air under pressure from said one housing one radial passageway, and

a sleeve in said one housing encircling said shuttle to provide abearing surface for said shuttle.

1. An air motor comprising a shell defining a piston chamber, onehousing threadingly engaged with said shell for closing one end of saidshell to define one end of said chamber and having a pair ofcircumferentially spaced radial passageways therein with one of saidradial passageways adapted to receive air under pressure, a piston insaid chamber movable in opposite directions, a second housing, means forthreadingly engaging said second housing with said shell for closing theother end of said shell to define a respective other end of saidchamber, a piston rod for said piston extending axially into said onehousing, a valve, a member received in the other radial passageway ofsaid one housing and having three passageways therein with one memberpassageway located intermediate the other member passageways, a ringseated against one face of said member with said ring having an openingtherein for receiving said valve in abutment with one face of saidmember, said ring opening having one pair of spaced sides defining aguideway for said valve and another pair of spaced sides each defining arespective limit position for said valve, a plate spring having a flatface overlappingly engaged with said valve, screw means securing saidspring and ring to said member for holding said ring in abutment withsaid member and said valve movably engaged with said member one face toselect one of said other member passageways for communication with saidone member passageway and the other of said other member passageways forcommunication with said one housing one radial passageway in accordancewith the limit position to which said valve is moved, an O-ring seatedbetween said member and ring and engaging the periphery of said onehousing other radial passageway for sealing said other radial passagewayagainst the passage of air, a cap overlapping said one housing otherradial passageway having a pair of cap passageways therein with one ofsaid cap passageways aligned with said member one passageway and theother cap passageway aligned with a respective one of said other memberpassageways, said cap one passageway adapted to communicate said memberone passageway with atmosphere, a single sealing means overlapping saidone housing other radial passageway interposed between said member andsaid cap and having means communicating said one cap passageway withsaid one member passageway and said other cap passageway with saidrespective one of said other member passageways, means securing said capto said member, a plurality of bolts threaded into said housing andextending through said cap and sealing means for sealingly securing saidcap and member to said housing witH said one cap passageway incommunication with said one member passageway and said other cappassageway in communication with said respective one of said othermember passageways, an axially extending passageway in said one housingcommunicating said one end of said piston chamber with the other of saidmember other passageways, a passageway in said second housing incommunication with said respective other chamber end, a conduit havingone end inserted into said other cap passageway, a pair of seriallyconnected fittings for connecting the other end of said conduit to saidsecond housing passageway to communicate said chamber other end withsaid other cap passageway and the respective one of said member otherpassageways, a shuttle relatively movably mounted on said piston rod andmovable with said piston rod and engaging said valve, a snap actingspring toggle assembly for driving said shuttle to a respective limitposition in response to said shuttle being moved to a respectivepredetermined position by said piston rod for moving said valve toopposite limit positions for communicating said one member passagewaywith a respective one of said other member passageways while the otherof said other member passageways is in communication with air underpressure from said one housing one radial passageway, and a sleeve insaid one housing encircling said shuttle to provide a bearing surfacefor said shuttle.